In the production of glass containers, such as bottles, jars, etc., is an automatic machine of the I. S. type, molten glass in the form of gobs is fed and distributed by means of a distributor, to the individual forming sections (generally eight) where the glass is shaped into a container.
The containers formed by each of the individual forming sections of the machine, while still hot, are deposited first on the dead plate of the respective section and from there they are pushed up to a transfer conveyor called a "carrier" which moves the containers of all of sections up to a "transfer" placed at the end of the carrier. The transfer regulates the movement of the containers separating them uniformly and changing their direction of travel by 90.degree., and deposits them one by one, uniformly spaced in a row, on a cross conveyor. Once a complete row is formed, a transfer device or mechanical pusher, simultaneously transfers all the containers from the cross conveyor to the lineal conveyor of the lehr, wherein they are exposed to a tempering process which eliminates the residual stress accumulated in the glass due to fast cooling during the fabrication process.
Pusher devices of the prior art generally consist of a pusher rod which pushes the bottles or articles advancing in a row on the cross conveyor, to the edge of the lehr belt. The movements of the pusher rod and the "transfer" are synchronized to coordinate the operation of loading the operation of loading glass articles into the lehrs. The pusher rod is generally coupled to a frame which transmits movements of pushing, elevation and return, for each row of bottles formed on the cross conveyor.
An example of known pusher apparatus may be found in U.S. Pat. Nos. 3,040,867; 3,184,031; 3,960,266 and 4,067,434.
Up to now, this type of pusher has been considered to be the most functional because 90% of the bottles produced are conveyed in the range of velocities that can be handled.
Nevertheless, the introduction of faster mechanisms such as the I. S. machine of ten sections and greater production output will require handling a greater quantity of articles in a smoother and faster way without causing the articles to fall during the pushing transfer.
In practically all the pusher apparatus in use today, was observed that during the same operation cycle, the pushing stroke time with respect to the return stroke time remained constant; the latter being independent of the operation speed (cycles per minute) of the pusher.
Taking into consideration the limitation of the pushers of the previous art to vary the pushing stroke time, it was observed that because on the return stroke no article is handled, and, therefore, a smooth path is not necessary, it is possible to increase the timing of the pushing stroke while decreasing the timing of the return stroke. This concept was claimed in the U.S. Pat. No. 4,480,741 (Mexican Patent No. 151,734). Basically the improvement consisted in the coupling of a quick return mechanism between the drive system and the cams of the pusher. Through this coupling, it was possible to increase the pushing stroke time (making it smoother) at the expense of the return stroke time.
Because of its very smooth pushing motion, the pusher claimed in U.S. No. 4,480,741 is particularly effective for handling unstable articles. However, there is a large variety of articles of medium and high stability which may be handled advantageously with a fast pushing action resulting in higher production volumes per unit of time. The disadvantage of the pusher claimed in U.S. Pat. No. 4,480,741 is that it lacks the versatility to handle the required high production volumes of the more stable variety of articles.
In order to eliminate the disadvantage of the pusher described in U.S. Pat. No. 4,480,741, a phase shifter mechanism or also called adjusting mechanism, was coupled between the quick return mechanism and the cams. Likewise, the phase shifter mechanism also can be coupled between the drive mechanism and the quick return mechanism. This way, the pusher can be adjusted in multiple pushing embodiments without the need to stop either the pusher or the production line, thereby avoiding time and production losses.
In this manner, the pusher of the present application permits adjustment of the velocity of the pusher mechanism at any instantaneous point throughout of the complete cycle of movement of the pusher.
Through the use of the present invention, any type of container can be handled in an optimum manner, for example, from slim and unstable containers to those of a large diameter, using the ideal pushing time independent of the velocity of the pusher.